Manufacture of bunched electric cables



(No Model.)

J. H. DALZBLL..

MANUFACTURE 0F BUNGHBD ELECTRIC CABLES.

No. 369,592. Patented Sept. 6, 1887.

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UNITED STATES PATENT OFFICE.

JOHN HENRY DALZELL, OF PITTSBURG, PENNSYLVANIA.

lw/IANUFACTURE OF BUNCHED ELECTRIC CABLES.

SPECIFICATION forming part of Letters Patent No. 369,592, dated September-6, 1887.

Application filedNoveinber2G,1886. Serial No. 219,961. (No model.)

To all whom, t may concern:

Be it known that l, JOHN HENRY DALZELL, acitizen ofthe United States,residing at Pittsburg, inthe county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in the Manufacture of Runehed Electric Gables; and I do hereby declare thefollowing to bea full, clear, and exact description ot the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invent-ion relates to an improved form of lead-covered electric cable, and the manufacture thereof.

Prior to this invention lead-covered cables containing multiple conductors have been made according to either of two general methods. One style, known as anti-induction cable, consists of a number of wires suitably insulated and covered with lead by the use of a hydraulic press in such manner that the distinctive feature otanti-induction is imparted-- namely, that each individual conductor of the iinished cable is entirely surrounded by a lead envelope, and entirely separated by the same material from the other conductors throughout its length. In the other style of cable, known as bunched cable, the metallic partition between neighboring wires is wanting entirely, the wires constituting a bunch, whose members lie close together, and are separated by the insulation alone. It is to this bunched cable that the present invention is directed. In manufacturing this class of cable the uniform practice has been to prepare the insulated wires for such cable by laying them up into a bunch or core,- then drawing the core so prepared into a lead pipe of somewhat larger internal diameter than the diameter of such core, and, nally, injecting under pressure an insulating compound liquefied by heat in order to drive out the air and fill up all`spaces with such insulation. As this insulation usually solidities on cooling, any flexing movement ofthe cable thereafter in reeling or unreeling causes it to crack, crumble, or otherwise become unreliable. This, to-

gether with the shrinkage in cooling, and uncertainty in the filling process, is liable to result in open or vacant places in the interior, which are regarded as objectionable. Again,

owing to the drawing-in process, to obtain the lead covering, such cable can be made only in short lengths, as it would be manifestly inipracticable to draw the core into and throughout a pipe of, say, halt" a mile length, and equally impracticable to fill the remaining spaces with insulating material to any degree of certainty of i'illing up all interstices. In

.my improved method of making such cable I 6o avoid these objectionable features,and am able to readily makethe cablein continuous lengths, limited only by the possibility of handling the finished product.

In carrying out my invention I make use of v a special form of hydraulic press, which is shown in the drawings.

Figure l isa vertical section of the press, while Fig. 2 shows in transverse section the two forms of hunched cables, .the upper being 7o as before described and the lower made acx cording to this presentinvention and embodying my improvements.

A is the water-cylinder ofthe press, having movable ram B,.eylinder A, by means of the therewith, are the guide-rods 7L, which pass 85 up through the head-block D as a guide, and carry at their upper ends the yoke t'. To the yoke i is attached a hollow tube or core-baule, extending down the axis through an opening in head-block D, through the lead-rani, (which is 9o bored to tit it neatly,) and into the lead-cylinder, where it ends just above the pipe-die l. The core-bar 7a forms a guide for the wires m, which enter it from a series of reels, R, suitably liung and preferably iu a circular arrangement from the ceiling of the room. The wires m are passed down through the core-bar, and at the start it is convenient to have them eX- teiid to and through the pipe-die b. Then the water-ram is lowered, leaving the top of the loo lead-cylinder clear -for pouring in the lead. Vhen this is done, the water-ram is caused to I Il To pnso i rise, and the lead-ram enters the leadcylinder and forces the lead into motion downwardly through the die. The wires m, being there also, are bunched together in a uniform and compact core by the pressure of the lead. The great pressure packs the hot and non-elastic lead closely around this core of wires and into the grooves on the exterior of the core due to the convexity of the wires and insulation. At the same time the pressure forms the lead covering, and in ejecting the latter draws the bunch into and through the press. lThe product is a solid compact cable, which requires no filling in afterward, because there cannot remain any spaces or interstices to fill.

In Fig. 2 I illustrate with seven wires. In the ordinary bunched cable these are so many circles, and, drawn into a lead pipe, s, necessarily leave quite a large amount of empty space, which is afterward filled, as hereinbcfore explained; but, under the powerful pressure applied in my process of making, the insulation, as seen at t, same figure, is forced to assume a polygonal form, filling all the inter-` nal spaces, and thelead covering fills perfectly the longitudinal or spiral grooves on the exterior of the bunch. The finished cable is thus produced at one operation and in any desired length, the cost of making is materially reduced, and a superior article is the product.

Care must be taken that the adjustment of the parts is correct, because, if the proper po sition is not obtained, no compression will take place, and the core of wires will not be drawn ,alon g by themere frictioual contact or impin gement thus afforded, while on the other hand excessive compression will have the effect of either breaking the wires or thinning down the insulation to a degree which detracts from the desired insulating capacity very materially. I reserve the right to include the special feature involved in another application to be led by me.

I claim as my inventionl. Thciniproved electric cable comprising a central bunch of wiresindividuallyinsulated and compressed together, so as to have no interstitial spaces, and a lead envelope for the whole, substantially as described.

2. The improved electric cable comprising acentral bunch of wiresindividuallyinsulated and compressed together so as to have no interstitial spaces, and a lead envelope compressed around said bunch and into its external grooves, substantially as described.

3. The process. of manufacturing hunched electric cables, consisting` in forming a number of insulated wires into a straight or spirallyarranged core or bunch,and then by hydraulic pressure compressing upon the same and into the external cavities thereof a continuous seamless envelope or covering of metallic lead, substantially as described.

4t. The process of manufacturing bunched electric cables, consistingin forming a number of insulated wires into a straight or spirallyarranged core, then compressing the same, and, finally, compressing thereon and into the external cavities thereof a continuous seamless envelope or covering of metallic lead, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

J Ol-IN HENRY DALZELL.

XVitnesses:

J. A. Chairmans, K. T. MEAD. 

